The immediate objective of this project is to isolate from human DNA the genes coding for the collagen polypeptides. These proteins comprise a family of polypeptides of extensive homology, whose pattern of expression is determined by unknown factors during differentiation and development. Isolation of the structural genes coding for these proteins, and a detailed analysis of their structure and mode of expression, may lend insight into some of the factors which control expression of these genes. For example, it may be possible to identify factors which permit expression of two genes simultaneously but preclude expression of a third. In addition, these studies may provide insight into the molecular mechanism by which the normal pattern of collagen synthesis is altered in a variety of connective tissue disorders such as Ehlers-Danlos syndrome, osteogenesis imperfecta and Marfan's syndrome, as well as in cells which have been transformed by oncogenic viruses. The genes will be isolated from libraries of human DNA sequences in recombinant bacteriophage and cloned in a strain of E. coli K12. They will be characterized by techniques which include mapping of restriction endonuclease sites; analysis of hybrids formed with collagen messenger RNAs using electron microscopy and nuclease Sl digestion; hybridization analysis of DNA fragments which have been separated by agarose gel electrophoresis; and DNA sequence analysis.